While we mainly think of the immune system as a shield against harmful bacteria, immune cells also make antibodies against the trillions of helpful bacteria that live in our guts. These antibodies keep friendly bacteria from venturing out of the intestines. But scientists don’t know whether our immune cells mostly target each species individually, or whether they largely recognize many microbial varieties at once. The answer to that question has implications for treating intestinal diseases, since ideally, therapies would target pathogens while leaving beneficial species alone.
A study published today (July 8) in Science Immunology reports that mice make antibodies that are extremely specific to the particular bacterial species living in their guts. The repertoire of antibodies in mouse guts is like a fingerprint: unique and dependent on which bacterial strains have colonized their intestinal tracts. This specificity toward certain bacterial species could mean that future immune-based therapies might target ...
